This invention relates to flexible bulk containers or bags used for flowable materials, and, more particularly to containers having shape retaining internal baffles.
Flexible bulk containers carrying flowable materials are generally made of fabric in the shape of a cube so that they can be stored, stacked, and transported in a minimal space. However, because the walls are so flexible, the flowable material deforms the walls, forcing them into a more cylindrical shape by bulging the sidewalls and rounding the corners. Various strategies of internal baffling have been employed to overcome this problem. The prior art is most effectively reviewed by U.S. Pat. No. 5,468,528 issued Nov. 21, 1995 to Schnaars et al.. It includes various panels and ropes joining adjacent side walls to restrain their outward bulging. To permit material to flow into and out of the corners enclosed by the baffle panels, various circular, oval, and triangular apertures have been cut in the baffle panels. Unfortunately, these apertures result in irregular stiffening or restraining forces being applied to the side walls as well as irregular packing of the material. This causes bulging of the side walls adjacent the apertures. These irregular bulges increase the packing space required by the filled bags and also cause the bags to lean irregularly, making stacking very unstable. Maintaining the sides of the filled bag as straight as possible is most important not only for shipment and storage, but also in handling the bag for dispensing, for example, when the bag must fit into the dispensing apparatus. At the same time, the addition of effective shape retaining elements should not increase the cost of the bags unnecessarily and should not interfere with effective filling and emptying of the flowable material in all corners of the bags.